HI, I have a 97 cobra I bought last summer. I put a kenne bell on it this fall, now I'm thinking of putting an IRS in it. My question is to those that have done it is how do you like it? I want a fun to drive, easy to live with car not a raw speed machine. I have a line on one with everything except calipers an rotors (was told I could use the ones on my 97) for around $850 shipped. Is it worth it or would I be better off improving the existing SRA? Thanks for any input.
any one converted to irs?
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you'll have to get a bunch of the steel lines and hoses for the brakes. other then that if i remember right as long as you have the right pinion flange youll be ok.
Both setups have their advantages and disadvantages. What is best for you depends of your budget and your plans for the car.
If I were you I would stick with what you have and do some upgrades including panhard bar, bushings, maybe LCAs and shocks.
Really the only problem with SRA is that the car wants to bounce sideways on corners at high speed. Just correct that with the parts I mentioned and you will be good to go.
If I were you I would stick with what you have and do some upgrades including panhard bar, bushings, maybe LCAs and shocks.
Really the only problem with SRA is that the car wants to bounce sideways on corners at high speed. Just correct that with the parts I mentioned and you will be good to go.
The IRS will do two things for you. It will give you better handling on rough (bumpy) surfaces. It will give you a softer ride for any particular level of handling.
It is heavier. It is more fragile. It will hop and as far as I know there is no way to stop it. The pick-up points weren't engineered properly, so it doesn't do all it could do from a handling perspective, considering what you give up. If you start making big horsepower you will need to buy very expensive half-shafts.
If pretty much all of your drag racing will be from a roll, you might be OK. If you prefer autocross or road racing, then the IRS might be worth it. My guess is that if you put the same amount of money in the solid axle set-up you have now, you'd probably come out ahead everywhere but in the comfort arena.
Bottom line if you make the swap: Your car will be slower in a straight line. It should be faster taking turns on a bumpy surface. It will be about the same on a smooth surface. It will ride better.
It is heavier. It is more fragile. It will hop and as far as I know there is no way to stop it. The pick-up points weren't engineered properly, so it doesn't do all it could do from a handling perspective, considering what you give up. If you start making big horsepower you will need to buy very expensive half-shafts.
If pretty much all of your drag racing will be from a roll, you might be OK. If you prefer autocross or road racing, then the IRS might be worth it. My guess is that if you put the same amount of money in the solid axle set-up you have now, you'd probably come out ahead everywhere but in the comfort arena.
Bottom line if you make the swap: Your car will be slower in a straight line. It should be faster taking turns on a bumpy surface. It will be about the same on a smooth surface. It will ride better.
There is some really great info and animated gifs here showing how the various types of Mustang suspension setups work:
Late Model Mustang Suspension Basics
Late Model Mustang Suspension Basics
If it were me, no way I would go to the IRS. Too many problems that are hard/really hard/practically impossible to fix. I'd go with the Steeda 5-link or something similar. It seems like I may have read an article on one of the Parnelli Jones Mustangs that had a Watts Link rear suspension. If that is being marketed, then it would also be a good alternative.
You might end up giving something up to a well engineered IRS, but you won't give up anything performance wise to the Ford/Cobra IRS.
You might end up giving something up to a well engineered IRS, but you won't give up anything performance wise to the Ford/Cobra IRS.
right now I'm leaning toward forgetting the irs. I may go with a panhard bar for now, then add the torque arm later. I do like the steeda 5 link but its so pricey.
RedTwilight
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Seems like you have had some frustrations with your IRS. But it's not as bad as you make it out to be. Yes the design is compromised from the very beginning. But so is the standard mustang straight axle suspension design.
I say it all depends on what you want to do with your car. Drag race, then by all means keep the straight axle. Road course/ auto-x, then a properly set up IRS may be in your favor. Keep in mind however that installing an IRS may put you in a higher running class.
Even the testing done by Maximum Motorsports has concluded that on the road course the IRS was better after the needed improvements.
Either way you choose it is apparent that the stock set up on either can be improved upon greatly.
The IRS Tech Article - SVTPerformance
I've got an '03 IRS waiting to go into my Cobra as soon as I get the bushings and Fore diff cover (and maybe coil overs). Now is the time to also change the gear ratio and/or posi unit while it's out of the car.
Either way you decide I'm sure you be much happier than with the factory set up. Good Luck!
I wouldn't bother. Mine is fine in my 04, I have no wheel hop with all my HP. Nitto tires cured all the wheel hop. But with only 9,200 miles on it, my diff cover is leaking already. I didn't do anything about it, and now it's worse I can see the wind is blowing it on my exhaust. Gotta fix it soon and add the diff brace.
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